/* Try to encode a string object in order to save space */
robj *tryObjectEncoding(robj *o) {
long value;
sds s = o->ptr;
if (o->encoding != REDIS_ENCODING_RAW)
return o; /* Already encoded */
/* It's not safe to encode shared objects: shared objects can be shared
* everywhere in the "object space" of Redis. Encoded objects can only
* appear as "values" (and not, for instance, as keys) */
if (o->refcount > 1) return o;
/* Currently we try to encode only strings */
redisAssert(o->type == REDIS_STRING);
/* Check if we can represent this string as a long integer */
if (isStringRepresentableAsLong(s,&value) == REDIS_ERR) return o;
/* Ok, this object can be encoded...
*
* Can I use a shared object? Only if the object is inside a given
* range and if this is the main thread, since when VM is enabled we
* have the constraint that I/O thread should only handle non-shared
* objects, in order to avoid race conditions (we don't have per-object
* locking).
*
* Note that we also avoid using shared integers when maxmemory is used
* because very object needs to have a private LRU field for the LRU
* algorithm to work well. */
if (server.maxmemory == 0 && value >= 0 && value < REDIS_SHARED_INTEGERS &&
pthread_equal(pthread_self(),server.mainthread)) {
decrRefCount(o);
incrRefCount(shared.integers[value]);
return shared.integers[value];
} else {
o->encoding = REDIS_ENCODING_INT;
sdsfree(o->ptr);
o->ptr = (void*) value;
return o;
}
}
/* Try to encode a string object in order to save space */
static int tryObjectEncoding(robj *o) {
long value;
sds s = o->ptr;
if (o->encoding != REDIS_ENCODING_RAW)
return REDIS_ERR; /* Already encoded */
/* It's not save to encode shared objects: shared objects can be shared
* everywhere in the "object space" of Redis. Encoded objects can only
* appear as "values" (and not, for instance, as keys) */
if (o->refcount > 1) return REDIS_ERR;
/* Currently we try to encode only strings */
redisAssert(o->type == REDIS_STRING);
/* Check if we can represent this string as a long integer */
if (isStringRepresentableAsLong(s,&value) == REDIS_ERR) return REDIS_ERR;
/* Ok, this object can be encoded */
o->encoding = REDIS_ENCODING_INT;
sdsfree(o->ptr);
o->ptr = (void*) value;
return REDIS_OK;
}
